Behavior of Masonry Walls and Building Envelopes Subjected to Differential Settlement Simulated with a GPGPU-parallelized FDEM

The failure behavior of dry-joint masonry walls and building envelopes subjected to differential settlement is simulated with a 3D GPGPU-parallelized combined finite-discrete element method (FDEM). Due to material degradation, mortar is usually lost or with little remaining cohesion in ageing masonry structures, and thus the dry-joint assumption can be reasonably accepted. Dry-joint masonry walls and building envelopes are composed of individual blocks, and exhibit high nonlinearity and discontinuity. Each masonry block is discretized into a number of four-node linear tetrahedral elements (TET4) in 3D FDEM. A finite element formulation is incorporated into each TET4 element, enabling decent predictions on contact forces and structural deformation. Using the FDEM, deformation and discontinuity of masonry structures can be represented in a more rational manner. Virtual experiments on masonry walls were conducted and the emergent phenomena were validated with the physical tests. A case study on a masonry building envelope subjected to differential settlement was investigated, and the influence of settlement profile on the failure behavior was studied. It was found that settlement within the plane of a single façade resulted in limited spatial effect. The three-dimensional effect was well exhibited in the cases of combined front-side foundation settlement, and the out-of-plane behavior was well identified by the FDEM.